ok, so a buddy and I are working on a 1983 550 sc. We cannot seem for the life of us to get it started, even with ether straight into the carb.

New plugs, are getting spark, seems to be recieving fuel from the tank (took apart petcock and everything seemed kosher).

What might be keeping it from wanting to kick over? right now we had to jump it off of another battery, starter is kind of cranking a little bit slow, but we can't even get the motor to catch AT ALL (even with fluid).

I do not know what the firing order is on these bikes or how to determine which plugs go where (in case they had been switched in previous tinkering) and the manual doesn't seem to help much here.

I am thinking most likely a timing issue? the bike was running fine for a while and slowly just got harder and harder to start and has sat for a year or 2 now. the old finger over the plug hole lets me think there is compression, but we are kind of at a loss for what to do here. We are going to replace the fuse thing between the battery and starter (some kind of relay) because that might be part of the problem i think with the starter running slow. Just drives me nuts that it won't even kick over at all. Am even thinking of pushing it down a large hill to see what hapens on a jump start.

how hard is the timing to set on these bikes? just an old fashoned timing light gun and go to town? we have a manual or 2, but are having hard time getting good troubleshooting out of there, but we know how many N-m to crank bolts to lol

Thanks, and if need any clarification i will try to help. We are fixing 2 bikes at once and got the other one running again (might be my future bike), and are both trying to learn something along the way

Thanks

Cliffs notes: bike isn't starting, i think it's timing or out of firing order... maybe you can help